U.S. patent number 4,657,868 [Application Number 06/428,172] was granted by the patent office on 1987-04-14 for apparatus for testing reactions.
Invention is credited to Rolf Saxholm.
United States Patent |
4,657,868 |
Saxholm |
* April 14, 1987 |
Apparatus for testing reactions
Abstract
A biologically active substance is incorporated in a unitary
body with a magnetically responsive material for carrying out
diffusion testing. These may be, microbiological, immunological,
serological and other biochemical examinations. The body is applied
against a substrate or medium by application of an external
magnetic field and a reaction region is produced at the site of the
body and is measured by means of a reader. In order to insure
deposit of the body on the substrate a predetermined location and
corresponding reading of the reaction region at such location, the
support for the substrate and the dispenser and rear are provided
with suitable releasable coupling and orienting devices such that
the dispenser and reader can be respectively engaged and oriented
on the support in predetermined secured positions.
Inventors: |
Saxholm; Rolf (1362
Billingstad, NO) |
[*] Notice: |
The portion of the term of this patent
subsequent to February 12, 1991 has been disclaimed. |
Family
ID: |
26809914 |
Appl.
No.: |
06/428,172 |
Filed: |
September 29, 1982 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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112407 |
Jan 15, 1980 |
4371624 |
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716684 |
Aug 23, 1976 |
4213825 |
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502107 |
Aug 30, 1974 |
3981776 |
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156738 |
Jun 25, 1971 |
3843450 |
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705539 |
Feb 14, 1968 |
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Current U.S.
Class: |
435/287.9;
422/504; 422/561; 422/69; 435/32; 436/515; 436/806 |
Current CPC
Class: |
C12M
23/10 (20130101); C12M 41/46 (20130101); C12M
35/06 (20130101); G01N 2800/52 (20130101); Y10S
436/806 (20130101) |
Current International
Class: |
C12M
1/22 (20060101); C12M 1/16 (20060101); C12M
1/20 (20060101); C12M 001/00 (); C12M 001/28 ();
G01N 033/54 (); C12Q 001/22 () |
Field of
Search: |
;422/55,56,57,69
;435/291,294,32,34,4,7,39,287,299 ;436/515,526,806,530,805 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Warren; Charles F.
Assistant Examiner: Tarcza; John Edward
Attorney, Agent or Firm: Roberts, Spiecens & Cohen
Parent Case Text
CROSS-RELATED APPLICATION
This application is a division of Ser. No. 112,407 filed Jan. 15,
1980, now U.S. Pat. No. 4,371,624, which is a division of
application Ser. No. 716,684 filed Aug. 23, 1976 issued as U.S.
Pat. No. 4,213,825 which in turn is a continuation-in-part of
application Ser. No. 502,107 filed Aug. 30, 1974 now issued as U.S.
Pat. No. 3,981,776 which in turn is a continuation-in-part of Ser.
No. 156,738 filed June 25, 1971 issued as U.S. Pat. No. 3,843,450
which in turn is a continuation-in-part of application Ser. No.
705,539 filed Feb. 14, 1968 and now abandoned.
Claims
What is claimed is:
1. The combination comprising: an article for carrying out testing,
said article comprising a test dose of an active substance which
may react with an agent of a medium when the article is brought
into contact with the medium, and metallic magnetically responsive
means incorporated with said test dose in a solid porous inert
carrier as a unitary body; and means for applying a magnetic force
to said metallic magnetically responsive means.
2. The combination as claimed in claim 1 wherein said means serves
to urge said test dose against said medium and into active
association with said agent.
3. The combination as claimed in claim 1 wherein said means serves
to remove said unitary body from said medium.
4. The combination as claimed in claim 1 wherein said test dose is
a specific substance related to said testing and distinct from said
metallic magnetically responsive means.
5. The combination comprising: an article for carrying out testing,
said article comprising a test dose of an active substance which
may react with an agent of a medium when the article is brought
into contact with the medium, and metallic magnetically responsive
means incorporated with said test dose in a solid porous inert
carrier as a unitary body; and means for applying a magnetic force
to said metallic magnetically responsive means to urge said test
dose against said medium and into active association with said
agent and to remove said unitary body from said medium.
6. The combination as claimed in claim 5 wherein said test dose is
a specific substance related to said testing and distinct from said
metallic magnetically responsive means.
Description
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The invention relates to diffusion testing in which the result is
indicated by a change in growth and/or other reaction. Such testing
includes tests which may be biological (i.e. microbiological,
immunological, serological and other biochemical tests inclusive of
clinical chemical tests) or chemical as long as they are suitable
for diffusion testing.
(b) Description of the Prior Art
Microbiological and immunological tests are often carreid out by
depositing an article for testing sensitivity, usually in the form
of paper discs, tablets, or similar bodies, containing biologically
active substances upon the surface of a solid or semi-solid
substrate or medium. In the case of microbiological testing, the
biologically active substance reacts with a culture of
microoriganism inoculated on or in the substrate or with various
substances in the substrate produced by the microorganisms, whereas
for immunological testing the active substance reacts with various
substances e.g. a serum added to the substrate or with various
substances produced by a microorganism.
Ths substances deposited are diffused downwardly into the solid or
semi-solid substrate to react with the aforementioned agents in the
substrate, i.e., the microorganism or substance produced by the
microorganism in the case of microbiological testing, and the added
substance or substance produced by a microorganism in the case of
immunological testing.
A common test of this type is the determination of sensitivity of
microorganisms, e.g. bacteria, to biologically active substances,
e.g. antibiotics, chemotherapuetics, etc. These experiments are
frequently carried out by inoculating the substrate with the
bacterial culture to be determined. Then the biologically active
substance, i.e. an antibiotic contained in an article in the form
of a paper disc or tablet, is deposited on the substrate, either
manually or mechanically, and then pressed lightly into contact
with the substrate with a sterile needle, tweezers or the like. The
disc or tablet is absorbent and the solid and semi-solid substrate
contains aqueous medium which is absorbed in the disc or tablet
whereupon the antibiotic is dissolved and diffuses into the
substrate. The substrate is then placed in an incubator and, after
sufficient time, the effect of the antibiotic is noted by measuring
the diameter of the circular zone of inhibition of the growth (i.e.
region of sensitivity) surrounding the article. Mention should also
be made of the use of biologically active substancs which stimulate
or enhance growth, i.e. of growth factors and growth requirements,
such as vitamins, amino acids, peptides, proteins, carbohydrates
and minerals.
Various other examinations which involve diffusion and change in
growth and/or other reaction in a solid or semi-solid substrate
e.g. radial immunodiffusion, can also be performed by the above
method. Additionally, since diffusable agents from the substrate
contained in the aqueous medium will diffuse into the article, it
is also possible to perform examinations which involve reaction in
the article.
In order to compare the test results of bacterial sensitivity to
various antibiotics, or the other biologically active substances,
it is essential that uniform and good contact between the article
containing the biologically active substance and the substrate is
obtained. It is also important to achieve as uniformly adjusted
contact as possible from one sensitivity test to the next in order
to compare the results and establish a basis for reliability.
A frequent source of error is determining sensitivity occurs when
the article containing the biologically active substance is
deposited or placed askew on the substrate. Because of incomplete
contact between the article containing biologically active
substance and the substrate, diffusion into the substrate will be
impaired since the amount of diffusion is a function of the contact
area. Good contact results when the intended contact surfaces are
in substantially complete and uniform contact thus resulting in
suitable and reproducible amounts of diffusion.
If uniformly good contact between the article containing the
biologically active substance and the substrate containing the
microorganism is not achieved, diffusion of the biologically active
substance into the substrate will not be uniform and consequently a
standard diffusion test procedure cannot be developed, since
diffusion is highly dependent on the size of the contact area. The
results of sensitivity tests determine to a large extent how
patients with infectious diseases shall be treated.
Heretofore, it was impossible manually to achieve a uniformly good
contact between biologically active substance and the
bacteria-containing substrate or medium from one sensitive test to
the next. Since laboratory technicians vary in manual dexterity,
proficiency, and work experience, it is not surprising that
uniformly good contact cannot be achieved from one sensitivity test
to another. Even greater variations in results can be expected
between different laboratory technicians.
Although many attempts were made to overcome the foregoing and
other difficulties none, as far as I am aware, was entirely
successful when carried into practice commercially on an industrial
scale.
SUMMARY OF THE INVENTION
An object of the invention is to provide an article containing an
active constituent suitable for testing various reactions i.e.
changes in growth and/or other reactions with an agent in a
substrate by diffusion of the active constituent in the article
into said substrate, or by diffusion of the agent contained in the
substrate into the article.
Another object of the invention is to provide a method and
apparatus for testing reactions using the above articles and
substrates.
A further object of the invention is to make the method and
apparatus operative automatically/under the control of an
operator.
According to the invention, a magnetically responsive means is
incorporated with the active constituent to form a unitary body
which can be brought into contact with the substrate by application
of an external magnetic force.
The active constituent may be an antibiotic for microbiological
sensitivity testing, or for immunological testing it may be an
antigen for testing antibodies in the substrate or vice versa.
In general, the active constituent reacts with the agent of the
substrate, either by diffusing into the substrate or by diffusion
of the agent into the article containing the active constituent or
by the combination thereof.
The article comprises a wettable or absorbent carrier which carries
the active constituent and is inert thereto, said carrier being
substantially insoluble in the substrate.
In further accordance with the invention, the apparatus for testing
reactions comprises a support for a substrate, dispenser means for
depositing a plurality of articles containing respective active
constituents onto said substrate in spaced relation, said
constituents undergoing varying, i.e. different reaction with an
agent in said substrate and producing detectable results, index
means for orienting the dispenser means and said support relative
to one another to predetermine the locations of said articles on
the substrate, and reader means correlated with said index means
for determining said detectable results at said predetermined
locations.
It is further contemplated according to the invention that the
articles may in some instances contain no active substance prior to
use but incorporate only the magnetically responsive material. The
articles are initially porous and dry i.e. they are formed, for
example, as paper discs and the active substance or test materials
are added to the discs either before or after they are deposited on
the substrate. Preferably the active substance or test materials
are in liquid form although it is also feasible to utilize them in
solid form such as powders.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a plan view showing tablets containing biologically
active substances placed at random on a substrate with varying
zones of inhibition;
FIG. 2 is a plan view showing six different biologically active
substances in respective carriers arranged in a predetermined
pattern on a substrate;
FIG. 3 diagrammatically shows in perspective an apparatus for
dispensing articles containing active substances on a substrate in
a petri dish provided with a permanent magnet;
FIG. 4 shows several embodiments of carriers with active substances
of various shapes and incorporating magnetically responsive
material;
FIG. 5 is a vertical section of one embodiment of a magnet
system;
FIG. 6 is a vertical section of a dispenser with a different
embodiment of a magnet system;
FIG. 7 is a schematic representation of a method of transmitting
and storing sensitivity test data;
FIG. 8 is an elevational view partly in section of a reading
apparatus;
FIG. 9 is a top plan view thereof;
FIG. 10 is a simplified circuit diagram of a reading apparatus with
a plurality of reading positions;
FIG. 11 is a similar view of a reading apparatus in which each
reaction zone is measured in succession with the same measuring
device;
FIG. 12 is a perspective view of a container with a cover
thereon.
FIG. 13a is an elevation view of a modified container with the
cover thereon;
FIG. 13b is a plan view of the container of FIG. 13a with the cover
removed;
FIG. 14 is a perspective view showing a modified embodiment of the
container with the cover thereon; and
FIG. 15 is a plan view of the container of FIG. 14 with the cover
removed.
DETAILED DESCRIPTION
In carrying out this invention, a petri dish or other receptacle
containing a solid or semi-solid substrate with a culture of a
bacterium or other microorganisms is associated with a means for
establishing a magnetic field such as, for example, one or more
permanent or electromagnets attached to the bottom of the dish or
incorporated in a supporting base for the petri dish. Thereafter an
article containing a biologically active substance and a
magnetically responsive material is placed on the substrate and,
through the action of magnetic force, forms a uniformly good
contact with the substrate, thus avoiding the use of manual or
mechanical pressure on the article to establish contact. The petri
dish is placed in an incubator and the biologically active
substance in contact with the substrate is then allowed a
sufficient period in the incubator to produce growth and/or other
reaction. Thereafter, a region or zone in which the biologically
active substance has inhibited, stimulated, or produced no change
in bacteria growth is visible to the eye. The measurement of this
zone or region of sensitivity results in an accurate measurement of
the sensitivity of the microorganism being tested to the particular
biologically active substance.
The method of accurately measuring the sensitivity of a
microorganism to a biologically active substance involves the steps
or forming a substrate containing a microorganism; placing an
article containing a biologically active substance having
incorporated therewith a magnetically responsive material on the
substrate (or on a predetermined position of the substrate);
causing a magnetic force to act on the acticle whereby the article
is urged against the substrate and forms good contact therewith;
allowing sufficient time for the biologically active substance to
act on the microorganism; and thereafter measuring the sensitivity
region surrounding the article. The magnetic field need not be
applied until the article is deposited, although I prefer to have
the magnetic force acting on the article at the time of its release
and prior to initial contact with the substrate so that the article
will be deposited in proper position on the substrate. After good
contact between the article and the substrate is achieved, the
magnetic force may be removed.
The articles may initially be blank and incorporate only the
magnetically responsive material, and solutions of active substance
can be added to the articles either before or after the articles
have been positioned on the substrate. This will be explained in
greater detail later.
This invention also provides an apparatus for testing the
sensitivity of a microorganism in which a receptable suitable for
holding a solid substrate (such, for example, as a petri dish) is
provided with means for applying magnetic field to the substrate so
that when an article which comprises a biologically active
substance having incorporated therewith a magnetically responsive
material, is placed on the substrate, the article is urged against
the substrate and establishes good contact therewith to permit
accurate measurements of the sensitivity of the microorganism to
the biologically active substance.
In addition, a mechanical dispensing means can be used for
dispensing the magnetically responsive articles with biologically
active substrate in random or predetermined positions on the
substrate, the dispensing means being provided with a plurality of
dispensing columns or tubular members. Also provided is an index
means to provide orientation between the dispensing means and the
receptacle to enable the articles with the bioligically active
substances to be deposited on the substrate in predetermined
positions. Such index means could, for instance, consist of
register marks on the receptacle or its support base at
predetermined distances which correspond to similar marks on the
dispensing apparatus at corresponding distances. The index means
could also consist of a detent or locking means.
In conducting the sensitivity measurements, various mechanical
reader means are provided to facilitate actual measurements of the
sentitivity regions surrounding the articles containing the
biologically active substances. For example, an instrument provided
with adjustable apertures arranged in a predetermined pattern
corresponding to the deposition points of the articles on the
substrate can be brought into alignment therewith by correlation
with the index means, and the respective apertures adjusted to
cover the sensitivity areas or respectively adjusted to grade
different degrees of positive reactions or no reaction. The grading
may be indicated by means of special switches or buttons. A mirror
reflex instrument is also a satisfactory means for determining
sensitivity. The general method of measuring sensitivity involves
the measurements of the diameter of the sensitivity region which is
normally circular and surrounds the article containing the
biologically active substance.
Although the invention will be discussed chiefly in relation to the
sensitivity of a microorganism to an antibiotic and vice versa, the
invention is broadly concerned with the use of articles associated
with active substances whose reactivity with an agent in a
substrate is detectable. Thus, for example, in immunological
testing, the articles contain an antigen to detect the presence in
the substrate of an antibody or vice versa. Also, for example, it
may be used for radio-immunodiffusion techniques and for
fluorescent immune diffusion techniques. In general, any detectable
reaction which occurs by means of diffusion of the active
substances in the article into the substrate or of the agent in the
substrate into the article is applicable to the present invention.
The reaction may be detectable by the eye, by a spectrophotometer
or by a radiation detector. The detectable change which may take
place within the article itself, may for example, be a test for
urease production by microorganisms by color change in the
article.
As to the type of physical connection existing between an agent and
a substrate, various expressions have been used herein to indicate
this connection. In this respect expressions have been used to
refer to the agent being "in" the substrate, and correspondingly
"on", "of", "contained in", "added to" and "associated with" the
substrate. In respect of the invention, the essential point,
whatever expression has been used, is a physical association
between the agent and the substrate. It will be understood that the
various terms employed, broadly should be interpreted to express
this fact.
In order for diffusion to be achieved, the article must be wettable
or absorbent to allow aqueous medium of the solid or semi-solid
substrate to contact the active substances to provide for
diffusion.
In the case of a carrier, such as a disc or a tablet for the active
substance, the carrier should be substantially insoluble in the
substrate to prevent any undesired influence on the diffusion
process and the delicate reaction mechanism taking place, for
example, by occurrence of unspecific reaction. The wettability of
the carrier is achieved by rendering it microporous in which case
wetting is effected by capillarity. In the case of paper discs,
they for example, may be absorbent to the extent that they absorb
approximately three times their weight in distilled water. The
active substance should desirably be substantially uniformly
distributed in the paper, and the paper should have no interfering
effect on the reaction. In the case of an antibiotic, the paper
should have no interfering effect either on bacterial growth or on
the action of the antibiotic. As an alternative to conventional
cellulose paper, various plastics satisfying the above conditions
may be used as the inert carrier. Also suitable are glass fibre
papers.
A dye may be incorporated in the article as coding means to
indicate the particular article to identify the reaction. The dye
should be substantially insoluble in aqueous medium and be inert to
the reaction e.g. have no interference with the antibiotic or the
growth of the microorganisms.
The articles may be supplied in a stack in a vacuum package.
Although the substrate might be a liquid, it preferably is a solid
or semi-solid which is microporous and possesses a high water
content in order to permit the diffusion mechanism to take place.
The substrate may initially be dry and the water added thereto
either directly or through the article itself. The substrate may be
a gel such as a starch, gelatin, silica etc., or it may be a paper
made on cellulose basis or a glass fibre paper. The most common gel
is an agar gel which possesses substantial strength even with very
high water content. Agar is very inert chemically and is suitable
for examining diffusion tests. In case of microbiological testing
the substrate will contain a nutrient and it must be sterile prior
to inoculation. The substrate is placed on a support which in the
case of microbiological testing is generally a petri dish or large
plate whereas in the case of immunological testing it may be a
coated plate. Generally the substrate has a substantially uniform
composition throughout its entire extent and is constituted of one
or more prescribed components in definite amount.
Referring now to the drawings, FIG. 1 depicts articles in the form
of tablets containing various antibiotics placed at random on the
surface of the substrate 1 in a petri dish 2 and surrounding the
individual tablets 3 to 8 are sensitivity areas 9 shown with broken
lines.
FIG. 2 shows six different antibiotic tablets 10 to 15 arranged in
a predetermined pattern characterized by mutual equiangular
ditances and radii R from the center of the petri dish 16.
FIG. 3 shows an apparatus for utilizing this invention in which a
base 17 is made of a permanent magnet and on the base there is
placed a petri dish 18 containing a substrate 19 and six different
antibiotic tablets 10 to 15 placed thereon corresponding to those
shown in FIG. 2. These tablets are placed in predetermined
positions by a dispensing apparatus 20 which consists of six
tubular members 21 to 26, preferably constructed from nonmagnetic
material, which at their lower ends are connected to a housing 27
and at their upper ends are connected to a supporting plate 28.
Each of the tubular members contains a stack of articles, the
articles originally having been supplied in a vaccum package. In
the housing 27, there are on each of the tubular members,
depositing mechanisms of known construction which are familiar to
those skilled in the art for releasing articles one at a time from
each tube in one operation. The supporting plate 28 is suspended
from an arm 29 which in turn is adjustably suspended in a manner
known to those skilled in the art in such a way that the dispensing
apparatus 20 may be moved up and down and can be swung from side to
side in order to facilitate a correct positioning of the dispensing
apparatus 20 relative to the disk 18. The dispensing apparatus can
be brought into correct position relative to the petri dish with
the register marks 30 and 31 on the petri dish and base
corresponding to the register marks 32 and 33 on the housing 27. It
is also possible to fix the dispensing apparatus and make the petri
dish movable. It is further possible to lock the petri dish on the
base and make either the dispensing apparatus or the assembly of
base and petri dish movable. Instead of register marks, detents or
other releasable locking means can be employed.
FIG. 4 depicts several embodiment of the article for testing
sensitivity in accordance with this invention and which may be
provided, for example, with a heavy magnetically responsive core as
shown in FIG. 4a. The core can be press fit into the article.
Alternatively, the magnetically responsive material could be in the
form of an annulus around the article. FIGS. 4b and 4c depict the
article in the form of a conical projectile to enable good contact
with the substrate. FIG. 4d shows the tablet with anchoring devices
which, for example, can be a magnetically responsive material such
as iron, and which prevent the tablet from recoiling when deposited
on the substrate. The paper discs and tablets may be impregnated or
admixed with a magnetically responsive material as shown in FIG. 4e
or the paper discs or tablets may be provided with magnetically
responsive components such as a foil attached by adhesion as shown
in FIG. 4f. In lieu of particles, the magnetically responsive
material could be in the form of a grid or foil embedded in the
article. In order to prevent any interference of the magnetically
responsive material with the reactants, an inert envelope may be
applied to the magnetically responsive material. In the case of the
embodiment shown in FIG. 4a, the entire core is covered with the
single inert envelope, whereas in the embodiment in FIG. 4c, the
individual magnetically responsive particles may be coated prior to
incorporation in the carrier.
FIG. 5 illustrates schematically a simple embodiment of magnet
system which can be used in the base of the apparatus when the
deposition points on the substrate are disposed in a cicle as in
FIG. 2. A permanent magnet comprised of two axially magnetized
Ticonal ring magnets 35, one on top of the other, is affixed by
means of an aluminum bolt 36 to a soft iron cup 37 which, together
with a circular pole piece 38 on the top of the magnet rings,
encircles a circular air gap facing upwards, which, like the
central bore of the magnet, is filled with non-magnetic material,
e.g. aluminum, as shown at spacers 39 and 40, to give the base a
smooth upper surface. The air gap has a mean diameter equal to the
diameter of the circle of positions (FIG. 2), which in turn is
determined by the positions of the outlets of the dispenser, and
the width of the air gap has to be adjusted to the height of the
surface of the substrate, so that a substantial field component is
able to act on the articles on the substrate. With the substrates
generally used, this height will normally be approximately 4-5 mm,
and the width of the air gap should in that case be about the
same.
Laboratory tests employing six different active substances as
illustrated in FIG. 2, and with a device as shown in FIGS. 3 and 5
have been used and by way of example mention may be made of studies
of the inhibiting effect of antibiotics in resistance
determination, where, on an inoculated substrate consisting of, for
example, a blood agar without a peptone additive, are deposited
paper discs containing such active substances as, for example:
Penicillin, sulphonamide, tetracyclin, erythromycin, methicillin,
fucidin, streptomycin, nitrofurantoin, amplicillin, and
nalidixin.
Articles can be used for other purposes than antibiotic sensitivity
testing, as previously mentioned, and by way of example the active
substance in the article may be an antigen or an antibody for
immunological testing of an agent added to the substrate.
Furthermore, the testing need not be biochemical, but may also be
purely chemical, such as, determination of pH of the substrate
within narrow limits by use of articles containing respective
chemical indicators undergoing changes of color at different pH
values.
It may also be mentioned that a number of active substances may be
supported on a common carrier. In such case, the active substances
may be disposed in spaced pre-determined locations on the common
carrier with the magnetically responsive material either
incorporated with the active substances, as in the previously
described embodiments, or maintained separate therefrom in the
spaces between adjacent substances.
FIG. 6 shows in greater detail another embodiment of magnet system
and a dispenser especially useful when discs in large numbers are
to be deposited. An aluminum base 41 is shown for centering and
supporting a dish 42 containing a substrate 43 and the base 41
contains a built-in system of magnets consisting of horizontally
magnetized permanent magnets 44 which lie parallel to one another
and are magnetized alternately each in opposite directions and each
of which is flanked by a pair of pole pieces 45 lying on edge which
form air gaps 46 facing upwards at the upper surface of the base.
Between each pair of magnetic poles there is a completely
symmetrical flux field with the plane of symmetry in the middle of
the air gap.
The dispenser 47 is supported by means of an arm 48 on an upright
49 on the frame 41 for pivotal movement in a horizontal plane from
the illustrated active position, which is determined by a stop, to
an inactive position where the dish 42 can be inserted and removed.
The apparatus contains vertical dispensing tubes 50 adapted to hold
stacks of discs 51 provided with magnetically responsive material,
for example, in the form of an iron foil affixed by adhesion. The
stacks of discs normally rest on a baseplate 52, which is fitted
with outlets 53 laterally displaced in relation to the relevant
dispensing tube 50. The bottom disc in each stack is moved to the
associated aperture by moving a pusher 55 against the bias of a
return spring 56. In the case illustrated, the pusher 55 is
provided with a straight translational guiding support which is
preferred in dispensers with a plurality of magazines, as opposed
to rotatable pushers, which are usually simplest when all the
magazines are on a common circle.
The base 41 and the dispenser 47 can be aligned with one another
such that the outlets 53 in the operating position are directly
above the air gaps 46. Each set of discs released will thus fall
parallel from the outlets 53 in symmetrical magnetic fields and be
positioned on the substrate 43 directly above the air gaps as shown
at 51', and be drawn into uniform contact with the substrate.
Should it be desired to regulate the strength of the magnetic
field, this may be effected by a pusher 57, which is supported for
movement across the magnets 44 at the bottom of the base 41 and the
pusher is fitted with pieces of soft iron 58, which in the
illustrated position lie directly beneath successive pole pieces
45, but by displacement can be caused to project more or less into
the space between paired pole pieces on the underside of the
respective magnets and thus more or less shunt the effective field.
By being moved to a central position underneath the magnet the
pieces of soft iron 58 can be made almost to short-circuit the
magnetic fields, so that the effect on the upper side is annuled if
it should be so desired, to guard against any magnetic action on
the discs while the dish is being removed. In order to remove the
dish without annulment, it is lifted from the holder 41 directly
upwards a small distance, i.e. in the direction of the magnetic
force so as not to disturb the position of the discs.
Among the sensitivity tests that can be undertaken with the
apparatus illustrated in FIG. 5 with more than six deposition
points, mention may be made solely by way of example of
determination of resistance to a bacterium such as Escherichia coli
of antibiotics such as penicillin, sulphonamide, streptomycin,
chloramphenicol, tetracyclin, ampicillin, colistin, cephalosporin,
nalidixin, nitrofurantoin, carbenicillin, and kanamycin.
The amount of magnetically responsive material in each article and
the strength of the field must, of course, be adapted to each other
in the light of the geometrical conditions, the orientation of the
field, the permeability of the components, etc., on the basis of
the contact pressure desired. For a properly adjusted contact this
will be the equivalent of the light manual pressure. With ordinary
disc-shaped articles of a diameter of approximately 6 mm, about 1
gram of force will generally be sufficient, and as an optional
parameter 2 grams of force produces a surface pressure of about
1/10 g/mm.sup.2.
The magnet system may also comprise small cup magnets placed under
the positions for the articles either in the substrate dish or,
more suitably, in a base on which it stands.
To bring about the desired effect without too strong a magnetic
field, the magnetically responsive material in a standard paper
disc should weigh slightly more than the rest of the disc, but
occupy less volume, and the amount will be only a very small
fraction of what would be required to achieve the same contact
pressure with the heaviness of an added weight.
Experiments with the contact pressure achieved with a system of
magnets as shown in FIG. 6 have been performed with Ticonal magnets
with an air gap of 5 mm, adjusted to provide a field intensity of
approximately 650 Gauss at a distance of 5 mm directly above the
air gap, i.e. at a height which should be quite sufficient to
accommodate variations in the depth of the substrate and the
thickness of the actual paper disc. The variations in field
strength from block to block at this height were quite
insignificant (.+-. approx. 25 Gauss). For a circular iron foil
with a diameter of approximately 5.5 mm and weighing approximately
20 mg, the height above the air gap for magnetic forces
respectively of 1 gram and 2 grams were 9.5 and 6.5 mm
respectively.
The experiment was repeated with an iron foil of the same diameter
and weighing approx. 12 mg (0.06-0.07 mm thick) and here the
heights were 8 and 5 mm respectively.
Similar tests have also been carried out with more powerful
(ceramic) parallel epipedic magnets of the Ferroxdure type, with
which an air gap of 6 mm generated a field intensity of
approximately 1250 Gauss at a height of 5 mm, while approximately
650 Gauss was measured at a height of 10 mm. The heights for
generated forces of respectively 1 and 2 grams were in the case of
the first foil 15.5 and 11 mm respectively and for the second foil
13 and 8 mm respectively. Such a system of magnets will thus be
unnecessarily powerful under normal circumstances where the amounts
of iron as mentioned above are used in the articles, but may be
suitable in the case of still smaller quantities of iron, or if an
extra pressure is desired, e.g. on articles to be drawn into the
substrate.
It is, of course, possible to replace the permanent magnets in the
illustrated system by electromagnets of similar dimensions which
can be regulated or switched on and off electrically.
In the conventional manner of dispensing articles onto the
substrate, they often tend to land in a somewhat oblique position
on the surface. Even a slight oblique angle on landing has a
disturbing effect on the possibility of providing good and uniform
contact in a predetermined position with respect to the
substrate.
Not only does this apply to light articles, which for inherent
reasons, need an addition of a slight external pressure to
establish good contact with the substrate, but also to
comparatively heavy articles.
A solid or semi-solid substrate, such as an agar substrate is as a
rule slippery and often somewhat elastic in its consistency.
Particularly, when heavy articles are concerned, the features
mentioned, will produce an undesired effect on the capability
establishing adequate contact in predetermined positions with the
substrate. Thus, deposition on the substrate by dropping articles
from a dispenser, will, especially when heavy articles are
concerned, often produce a slight, although noticeable, and
disturbing rebound effect. This is due to the somewhat elastic
consistency of the substrate mentioned. Furthermore, the kinetic
energy of the heavy articles effected by the rebound from the
substrate, especially in combination with the tendency of the
articles to make a skew landing, and, with the slippery substrate,
has a detrimental effect with respect to adequate positioning. The
articles will more or less tend to slide out of the desired
location, without establishing good and uniform contact.
The invention makes it possible to avoid the obstacles disclosed
above. Thus, by means of magnetic forces it is possible, according
to the invention, to deposit articles on the substrate in good and
uniform contact therewith at desired predetermined positions.
Furthermore, if magnetically responsive material, for example,
iron, added to an article, amounts to such a degree that the
article becomes heavy, it is possible, according to the invention,
to use a relatively weak magnetic field so as to create a weak
magnetic force able to overcome the rebound and sliding effect
produced during the initial contact between the article and
substrate during deposition. A strong magnetic field may under
these circumstances, using an article incorporating a relatively
substantial amount of magnetically responsive material, create a
magnetic force so strong that on being added to the force of
pressure created by the heaviness of the article, results in an
over-all pressure which may damage the supporting strength or
structure of the substrate.
Articles may become heavy not only due to the added weight of the
magnetically responsive material itself, but also to a combination
of the magnetically responsive material, for example, iron, and
other materials, for example, lead. The strength of the magnetic
field to be used according to the invention, has to be adapted to
the amount of iron or other magnetically responsive material
present, on the basis of the initial contact pressure desired.
An askew landing of a heavy article on the substrate will seriously
interact with the rebound and sliding effects, thereby seriously
disturbing the possibility of positioning the article in good and
uniform contact with the substrate in a predetermined position.
According to the invention, it is possible by magnetic means to
guide the article in a blanced position or equilibrium during the
flight, thereby avoiding the interactions mentioned.
In this connection it should be recalled that according to the
invention, it is possible by means of magnetic forces to eliminate
the disturbing effects of rebound, sliding and askew landing of an
article being dropped onto a substrate. As disclosed above, heavy
articles are particularly liable to create rebound and sliding
effects by the initial contact with a substrate.
It should be recalled that articles have been disclosed for
providing good contact with deeper layers of the substrate, for
example, articles in the form of conical projectiles. Such articles
may also be in the form of balls. Also these articles may be made
heavy by added weight, for example, by addition of a substantial
amount of magnetically responsive material, for example, iron. They
may also be subjected to a rebound effect from the substrate in
response to the initial contact as a result of the dropping. Also
in this case, it will be possible by means of magnetic forces
according to the invention to eliminate the rebound and sliding
effects by adapting the strength of the magnetic field to the
amount of magnetically responsive material present, on the basis of
the initial contact pressure desired.
The magnetically responsive material added to the article may be
supported and carried by a carrier of the article.
The invention is highly suitable also for prediffusion techniques
i.e. pretreated substrates which are at present used by only a few
laboratories. In the method currently employed with these
techniques, antibiotic bodies are placed by hand or by means of a
dispenser on the substrate before inoculation is carried out. They
are then lightly pressed by hand into contact with the surface of
the substrate. After a suitable diffusion time, the bodies are
manually removed, and inoculation performed. This technique suffers
from the certain disadvantage that the risk of contamination is
considerable owing to the large amount of manipulation required.
Furthermore, the identity readings of the reactions are made
difficult and uncertain since the articles have been removed from
the reaction sites before the readings take place.
The invention makes it possible by means of magnetic forces not
only to deposit the bodies on the surface of the substrate, but
also to remove them. This can be done, for example, by turning the
substrate dish upside down and removing the bodies by means of the
magnetic force generated by the magnet means in the base, the
bodies being collected on paper, or other material. The identity of
the reaction may be mechanically determined by their correlated
positions with respect to the register marks 30, 31 which were
employed as an index means for the position of the dispensing
apparatus relative to the dish and base.
The articles may, in some instances, contain no active substances
prior to use, and these blank articles, according to the invention,
incorporate magnetically responsive material.
For testing or assaying purposes, solutions of active substances or
test materials prospective of containing active substances, will be
deposited by the laboratory workers into the articles, for example,
paper discs.
It is possible for the active substances or test material
prospective of containing active substances to be in solid form,
for example, a powder. In this case liquid substrate will diffuse
into the article and dissolve the solid test material resting on
the top of the wettable carrier, whereafter the test material will
diffuse via the carrier into the substrate.
The addition of active substances or test materials prospective of
containing active substances may be made either after the articles
have been positioned on the substrate, or before. In the latter
case, when the additive is a liquid, the articles may be dried
before they are positioned.
Positioning of the articles is carried out according to the
invention, i.e. by magnetic means in order to provide a good and
uniform contact with the substrate. Dispenser means comprising
index means, and aligning procedures according to the invention are
used in order to position the articles in predetermined spaced
positions as a prerequisite to using the reader means of the
invention.
The use of primarily blank articles incorporating magnetically
responsive material will be very useful for an assay technique and
thereby for the search for and exploration of new active substances
for the purpose of manufacturing. The procedure is applicable to
improvement of manufacture and to control of products.
The use of primarily blank articles is also useful for carrying out
assay techniques in diagnostic laboratories, for example for the
purpose of determining whether or not an active substance, for
example, an antibiotic, is present in a tissue liquid, and if so
for determination of its level of concentration.
It is emphasized that the method of this invnetion is essentially
equally applicable to regular diagnostic techniques as to assay
techniques. Thus, the method remains basically the same whether one
is testing the activity of an active substance or whether one is
testing the activity of an active substance against an agent. The
difference lies solely in the object of the tests, apart from the
distinction mentioned in those cases in which primarily blank
articles are used instead of articles primarily containing active
substances.
The reactions and the reading of the results are essentially
independent of whether articles primarily containing active
substances or whether blank articles to which active substances or
test materials are added, are being used.
In connection with the exploration of potential vendible products
and with control examinations, it should be emphasized that the
invention, as in diagnostic testing, in a very high degree will
improve the reliability of the tests carried out by providing more
reproducible results and avoiding errors.
Additionally, the increased speed and the reduced cost of labor
provided by the method of invention, makes it possible to
investigate a much larger number of potential vendible products and
to carry out a greatly increased number of control tests.
The value of this is especially high, because of the fact that the
evaluation of the results of tests, requires a considerable number
of replicate tests in the various runs of investigation in order to
produce the necessary statistical significance.
For this purpose the so-called large plate method advantageously
may be used, because it is very suitable for carrying out
laboratory diffusion tests in accordance with an assay design. Very
suitable in this connection is the use of the embodiment of magnet
system and dispenser system shown in FIG. 6. Thus, the embodiment
is especially useful, as in the case of large plates, when articles
in large numbers are to be deposited, and the deposition points on
the substrate are to be disposed in straight lines parallel to each
other.
It will be understood, that in individual tests, the test
components, i.e. the active substance and the agent, may prove to
be inactive, in which case no reaction will occur, and the terms
employed to refer to the test components should be interpreted to
include this possibility.
Furthermore, the test materials may or may not contain test
components, i.e. active substance or an agent. For example, one may
intentionally use a well-known active substance as a test
component, or one may use test materials prospective of containing
active substances, such as when test materials are dropped into
blank articles with a view of finding out whether or not the
materials contain active substances capable of reacting with the
agent present in the substrate, and if so, determination of their
potencies or levels of concentration.
It is emphasized that an active substance or constituent added to
an article for testing purposes, should be broadly interpreted to
include both the intentional use of an active substance as well as
the alternative use of a test material prospective of containing an
active substance. Furthermore, it will be understood that a test
material prospective of containing an active substance may be any
type of test material suitable for assaying or analysis either pure
or composite.
FIG. 7 is a schematic representation combining several features of
the invention in which 101 represents the depositing or positioning
of the articles containing biologically active substance on the
substrate, 102 represents the incubation period, 103 represents the
sensitivity reading, which for example, may be taken with a mirror
reflex unit in which the results in such a case go straight to the
data processing unit 104 and from there to various receivers 105,
106 and 107. When making visual readings of sensitivity, use is
made of branch 103' with the results being transmitted to data
processing unit 104 and from there to the various receivers 105,
106, and 107.
Another feature of this invention provides a system which achieves
mechanization of primary noting (that is the direct reading and
compiling of sensitivity data) for suitable bacteriological
examinations and other suitable examinations, such as, for example,
immunological or serological reactions taking into account the
requirement for the possibility of visual and personal control and
supervision. The invention contemplates a method for determining
change in growth or other reaction in a solid or semi-solid
substrate in connection with the primary noting of data and it is
characterized in that the articles containing the subtances
bringing about the reaction are arranged on the surface of the
substrate in a pattern of predetermined positions so that the
sensitivity reactions, which can be read by a manually operated
instrument having indicators arranged in oppositely disposed
positions, can be checked visually while at the same time the
indications may be read by machine, transmitted to a data
processing unit where it can be assembled and coded, if necessary,
and, thereafter, transmitted to a receiver where it can be stored
for ultimate use and then subsequently read out when needed.
The identity of each reaction is determined by its position, a
condition which is machine sensitive in one operation not only for
one reaction but for the entire series of reactions in the pattern.
It is also possible, in accordance with this invention, with the
help of suitable apparatus, indicators, and the like, in a simple
manner to indicate the results of the reactions on the basis of the
laboratory technician's experience. These indications are also of
such a nature that they are machine-sensitive and may be
transmitted and stored.
The determination of the identity of the reaction and the
indication of the result from visual observation may, according to
the invention, be expediently combined in the same apparatus.
Referring to FIGS. 8 and 9 therein is seen petri dish 18' placed in
a reading apparatus 60 for detecting the sizes of the zones of
inhibition 9 surrounding the articles 3-8. The base 61 of the
reading apparatus may contain electronic equipment for processing
the measuring results. In the particular embodiment, it is assumed
that the substrate and the bottom of the dish 18' are transparent
and that the dish is centered on a glass plate 62 at the upper
surface of the base 61 and illuminated from below by light sources
schematically indicated at 63. Correct angular positioning of the
dish 18' on the base 61 is ensured by corresponding register marks
64 on the dish and 65 on the base. Readings are made visually
through apertures in a holder 70 which is pivotably mounted in a
horizontal plane about a column 71 on the base, so that it can be
swung aside to facilitate insertion and removal of the dish, the
operative position of which is determined by a stop 72. The
position of the stop 72 is correlated with the register marks 64,
65 so that the apertures in holder 70 will be exactly above the
articles 3-8. In the apertures of the holder 70 are fitted iris
diaphragms 73, the apertures of which can be adjusted by means of
adjusting rings 74 which are accessible on the upper side of the
cover 75. On the holder 70, under the cover, are means which sense
the settings of the apertures electrically and which, via flexible
leads running through the hollow supporting column, 71 are
connected with electronic equipment in the base 61.
The means for sensing the aperture setting may be, for example,
voltage dividers as shown at 74' in FIG. 10. However, for the sake
of simplicity, in this figure instead of iris diaphragms 73, slot
diaphragms 73' are shown having opposite indicator edges which can
be adjusted independently of one another to opposite extremities of
the respective reaction zones. One side of the indicator at all
reading points is mechanically connected with the end of the
voltage divider which has a negative potential, while the other
side is connected to the sliding contact of the voltage divider, so
that the potential on each sliding contact serves as a measure of
the size of the relevant aperture and thus of the measured zone
diameter. With an embodiment employing iris diaphragms as in FIGS.
8 and 9 it will be possible to use a similar device with a fixed
voltage-divider resistor on the holder and with sliding contacts on
the adjusting rings of the diaphragms, by means of which the
diaphragms are adjusted to cover the relevant zones.
The measuring voltages from the sliding contacts thus constitute
analog data and are conducted via separate leads from the sliding
contacts to an adapter 76. This may comprise, for example, an
analog digital converter for conversion of the an data to a binary
code and may be programmed to coordinate individual measuring data
with data relating to the relevant active substances, these being
identified by the individual leads for the respective positions.
From the adapter, the data so coordinated can be delivered for
registration either directly in a computer or on a punched tape or
similar medium, which each time is first provided with
idenification data and then with measuring data. Relaying from unit
76 can be done either in turn as and when measurements are made, or
at the end, after all the indicators have been adjusted, as the
leads from the sliding contacts can be connected to contacts in a
multiplexer which is released by pressing a button 77.
Should there be more reading positions than occupied positions, the
sliding contacts in the unoccupied positions will be in the zero
position; this will have no effect on the remaining readings. And
if by chance a position should be missed in the reading process,
the only consequence will be that the measurement in question will
be lost, as all the measurements made will remain alloted to their
respective, correct identifications.
Although in FIG. 8 the articles containing the active substance are
deposited on the sustrate during measurement it makes no difference
if the articles have been removed from the substrate before
measurements are made, as for example in prediffusion techniques,
as measurement is only undertaken on the formed zones. It will be
recalled that in prediffusion techniques, inoculation of the
substrate is performed after the articles have been in contact with
the substrate for a certain period in which diffusion takes place
and subsequently the articles are removed.
FIG. 11 shows a simpler embodiment of reader apparatus, employing
only one measuring instrument, in the form of a sliding gauge 78
similar to a micrometer. The substrate is illuminated by a light
falling onto it so that under normal circumstances it will not be
necessary to provide illumination from below through the bottom of
the dish. The dish is mounted on a base or turntable supported on a
rotatable shaft 79. The indicators of the gauge 78 are adjusted to
the diameter of the reaction zone, which is indicated by a broken
line at 4'. The gauge supports a voltage divider 74" fitted with a
sliding contact 80 mechanically connected to a movable indicator 81
of the gauge. The voltage on the sliding contact thus again
constitutes a measure of the measured zone diameter d and is
relayed to an adapter 76'. Voltage is also applied to a selector
arm 82 which is insulated and mounted on the shaft 79 and in turn
cooperates with fixed contacts placed at angular distances
corresponding to the various positions in the dish when this is
properly aligned at an index or measuring position. The fixed
selector contacts are connected in turn via separate leads with the
adapter 76'. The measuring instrument 78 is employed at the same
location and the dish is rotated on a turntable to bring the
measuring zones to the instrument. The instrument can be supported
on a suitable radial guide. Alernatively, the instrument may be
connected with the unit 76' by flexible connectors so as to be
portable. The axle 79 of the turntable is turned to turn the dish,
after each reading, through an angle corresponding to the angular
spacing between the measuring zones. In this case the registration
are performed successively, in other words, for example, by the set
position amd the set voltage being registered coordinately for each
individual reading by pressing a button 77'.
Instead of using voltage dividers which cooperate with an analog
digital converter in the adapter, it is, of course, also possible
to use other components for the purpose, e.g. to fit binary
position encoders with direct mechanial connection to the measuring
instruments.
Finally, it is possible to use the apparatus as shown in the
drawing not only to measure diameters, but also to supply data for
indicating the absence presence of a reaction or for grading
positive reactions, by assigning to such observations specific
settings of the measuring instruments. This is applicable not only
for diffusion testing but also for testing not involving diffusion
such as, phage typing. In fact, it is applicable to various
biochemical and chemical tests, such as clinical chemical tests;
so-called spot tests; and immunofluorescent techniques. Such
biochemical tests may include, for example, color change in the
article itself, e.g. in a test for urease production by
microorganisms.
The identification of the reaction and indication of its result may
be fed into a central data unit as two machine sensitive functions.
In this manner, it has been possible to establish a primary noting
by machine of bacteriological or other data in machine contact with
a central data processing unit with the excellent advantages
offered. Such advantages, are, for example, saving in recording,
storing, communication and analysis of the data.
In the first phase of data processing, the primary noting handles
the basic material on which the subsequent phases of the process
build. By mechanical means primary noting is much more reliable
than manual means, and faster registration and flow is thus
possible. During manual primary noting of data, errors may easily
arise, not the least of which occurs in bacteriological and similar
examinations (for instance, serological examinations) in which the
reading or collecting of data can be monotonous. The reactions
which are uniform and usually occur in large numbers are as a rule,
only differentiated under the guidance of memory. As identifying
marks, various colors or symbols on the tablets or other articles
containing biologically active substances which occur in the
reactions are used, or the marks may be indicated by typical
laboratory markers (such as, for example, a grease pencil) on the
bottom of the petri dish. When at the same time measurements have
been made and noted manually, the possibility of error arises.
Errors such as these in primary noting are very difficult to
discover and correct. In consequence, errors are introduced in the
basic material with all the complications which are later involved
in further processing. Results may be interchanged, and the faulty
data is compiled concerning what has been found in the patients.
This, in turn, could lead to incorrect treatment. Incorrect
measurements or notation can also result in many other
complications. Thus, errors in primary notation can lead to
complications in the detection of infectious diseases and the large
group of epidemics caused by microbes. It is evident that by the
use of the system in accordance with this invention errors of this
nature are kept to a minimum and a high degree of reliability can
be placed on the data collected and stored through the electronic
data processing unit.
A central health registry system can be established in accordance
with this invention. The objective is to build up an intergrated
communication system between various sectors of community health
services. By way of example, it shall be possible when admitting a
patient to the hospital to speedily and reliably collect
information from a central storage unit with respect to any earlier
stays in the hospital or other examinations which may have been
made. New findings of possible interest may similarly be at the
disposal of the attending physician. It must be possible to provide
cumulative transcriptions concerning findings in patients. A
correct basic material plays here, as elsewhere, a decisive role,
the effect of which the invention will be able to realize with
regard to the examinations made. Similarly the effect of the
information on the realization of a speedy flow will be of vital
significance, particularly in acute and dangerous cases.
In the bacteriological laboratory, it is, generally speaking,
unusual to carry out the work, with a system in mind whereby a
growth or a reaction is to be placed in a position or in a pattern.
Normally, the inoculation of the material of the placing of the
reactions occurs at random on the surface of a substrate or in a
tube containing a liquid substrate.
Viewed as a whole, the method of this invention for collecting,
transmitting and storing laboratory information proceeds in
distinct phases or steps.
In the first phase the agent is inoculated on or in the substrate,
and as a rule the positioning of articles is carried out the
effects or reactions of which is to be tested. Such articles may
include antibiotics whose sensitivity to microbes is to be
determined.
In the second phase incubation is carried out in order to develop
the growth and/or other reaction. The container in which the
inoculated substrate lies is placed in an incubator usually at
about 37.degree. C. It usually remains there 18 to 24 hours.
Sometimes the period may be shorter, but it may also extend up to
several weeks.
The conditions should desirably and substantially be under control.
If, in a particular technique there is required a secondary
application, as, for example, of an article containing another
substance, this should desirably be done also under control
conditions, such as, control of time at which it is applied,
control of amount added and of the site at which the addition takes
place.
In the third phase the results are read and their nature and extent
recorded.
Very wide-spread is, for example, the usage of antibiotics in the
form of small, at least approximately, circular tablets, paper
discs, and similar bodies containing the antibiotics. These are, in
accordance with this invention, guided by means of the magnetic
attraction into the desired position on the surface of an
inoculated substrate in good contact with the substrate. After an
incubation period the effects are automatically read off under the
control of the operator by measuring the spread of area of
sensitivity which is formed around the individual antibiotic
bodies.
In contradistinction, the prior art requires manual procedures
which are exacting and demanding, and above all, time consuming.
This is becoming a serious problem due to the increasing numbers of
such tests in laboratories. Such manual procedures as positioning
the individual bodies requires skill and is laborious while
additionally, manual reading is cumbersome and time consuming and
must be carefully made in order to obviate erroneous readings which
could have fatal consequences as the treatment of the patient
concerned is decided, on the basis of such sensitivity
determinations.
In accordance with the invention, this is avoided by automatically
locating the bodies containing the antibiotics at specific
predetermined locations and correlating, the reading or measurement
of the reaction zones at said predetermined locations whereby for
each reading, two signals are always produced, one for the
magnitude of the reading, the other for the identification
thereof.
In order to insure that the location of the reaction region will
conform exactly with the reading position it is necessary to
correlate the deposit of the articles with the position of the
reader. In order to achieve this the invention contemplates a
simplified means for establishing releasable coupling between the
support or container for the substrate and the respective dispenser
and reader.
Referring to FIGS. 12-15 therein are shown various constructions of
orientation and releasable coupling means for proper orientation
and support of a dispenser device and a reader device on the
container for the substrate.
Thus referring to FIG. 12, therein is seen a contained 101 with a
substrate 119 therein. At the bottom of the outer periphery of the
container 101, there are placed two protuberances 102, 103 in
angularly offset relation. Protuberance 102 is triangular and
protuberance 103 is rectangular. The reader device and the
dispenser device are each provided with a casing 104 having notches
105 and 106 of a shape corresponding to the protuberances 102 and
103 such that when engaged therewith the casing 104 is angularly
oriented and locked with the container 101. Thereby, the position
of the dispenser device and reader device will be fixed with
respect to the container and the accuracy of reading of the
dispensed articles on the container will be insured.
FIGS. 13a and 13b show a modified arrangement and herein the bottom
of the container 101 is provided with a central recess 110 and the
periphery is provided with a triangular groove 111. The dispenser
and reader are formed with base 112 having an upstanding pin 113
which fits into the recess 110 and an upstanding post 114 of
triangular shape for fitting into groove 111.
FIG. 14 shows a modified arrangement in which the container 101 is
formed with an annular flange 115 having two slots 116 and 117
therein of different shape, slot 116 being triangular and slot 117
being rectangular. These slots accommodate posts 118 and 119 formed
on a base of a respective dispenser device and reader device.
In FIGS. 12 and 14, the container 101 is shown with a cover 120
thereon. The flange 115 in the embodiment of FIG. 14 extends
radially outwardly a distance equal to the rim of the cover
120.
It will be understood that the recesses and corresponding
projections can be formed on the respective elements in any
suitable fashion, Additionally, it is to be understood that the
cooperation of the container can be made in the same manner as
described above with the magnetic base.
Although the present invention has been described in conjunction
with preferred embodiments, it is to be understood that various
modifications and variations thereof will become apparent to those
skilled in the art without departing from the spirit and scope of
the invention as defined in the appended
* * * * *